Wing In Ground Effect Hydrofoil Vessel

ABSTRACT

The present invention concerns a marine vehicle that derives its lift and control forces and moments from a combination of the following mechanisms; aerodynamic effects on a lifting surface in ground effect, hydrodynamic effects on submerged hydrofoils, planing forces on deployed winglets, and hydrostatic effects on submerged elements. The portion of the overall lift and control forces that is contributed by each mechanism varies as a function of vessel speed. The hydrofoils may be subcavitating, supercavitating, transcavitating or superventilated. The three lift and control mechanisms are individually found on existing Wing-In-Ground Effect (WIG) vehicles, hydrofoil vessels, and multi-hull vessels but have not previously been combined in the manner described. The present invention combines these three elements to achieve high lift-to-drag ratios, low fuel consumption, good maneuverability, low noise, low vessel draft, low vessel motions, and operation in higher sea states at all relative headings to the wind and waves. Applications of this craft include both civilian and military uses.

The elements of this invention include an aerodynamic lifting surfaceoperating in ground effect, two or more hydrofoil surfaces generatinglift and control forces below the water surface, and downwardlydeployable winglets that allow a marine vessel to transform between aWIG-hydrofoil to a catamaran vessel as the vessel's speed is changed.The position of the winglets may be continuously varied to change theclearance between the wingtips and the water surface, thereby changingthe lift coefficient of the wing in ground effect. The craft has movableflaps at the trailing edges of both the aerodynamic and hydrofoillifting surfaces. The craft may be propelled with either an in-waterpropeller or an in-air propeller. The combination of lift and controlmechanisms enables the vehicle to achieve high lift-to-drag ratios overa wide range of operating speeds in the presence of waves. Unfamiliarterms used in this document are defined in List 1 Term Definition WingIn Ground Effect An air vehicle that experiences enhanced Vehicle (WIG)lift and improved lift-to-drag ratio as a result of operation within onechord length of a fixed surface. The effect is characterized by anincreased pressure on the bottom of the lifting surface. Air CushionVehicle A vehicle that has a flexible skirt that (ACV) forms a cavitybeneath the vehicle. Pressurized air is pumped into the cavity to spreadthe vehicle weight over a large footprint. Surface Effect Vehicle Avehicle that has two or more rigid hulls (SES) in the water that, inconjunction with forward and aft skirts, form a pressurized cavity thatcan spread the vehicle weight over a large footprint. Hydroplane Avehicle that obtains both aerodynamic and planing lift. The planing liftis obtained from one or more hulls that remain in contact with the watersurface. The aerodynamic lift is obtained from a wing that joins thehulls or extends beyond the hull(s). Subcavitating A hydrofoil on whichthe pressure on the upper surface does not go below the vapor pressureof water and where no cavitation occurs. Supercavitating A hydrofoildesigned to allow the pressure to drop below vapor pressure with acavity forming adjacent to the surface of the foil. Superventilated Ahydrofoil designed to inject or vent air hydrofoil into a low pressurecavity on the upper surface of the foil thereby reducing drag on thefoil and enabling the foil to be free of cavitation damage at highspeeds. Transcavitating A foil that has deployable appendages orelements that effectively change the hydrodynamic shape to allow atransition from subcavitating to supercavitating regimes. Lift-To-DragRatio A measure of the vehicle's efficiency that is obtained by dividingthe total lift (under static conditions, this is the vehicle weight) bythe drag when operating at speed.

FIG. 1 is a perspective view of the marine vehicle with the winglets 20in the horizontal position as they would be at vehicle speeds of twentyknots or more. Shown in this figure are the controllable hydrofoils 21mounted on struts 24 and the main body of the hull 22. Aerodynamic flaps23, located at the aft end of the main body, are used to control theaerodynamic lift generated by the flow of air over the hull. In thisvariant, a main in-water propeller 25 is located behind the aft strutwhere it is driven by an inclined shaft.

FIG. 2 is a perspective view of the marine vehicle with the winglets 20in the vertical position as they would be at speeds below about twentyknots. In this condition, the winglets 20 provide the buoyancy tosupport the vehicle weight. There is a hinge line 26 at the junction ofthe winglet and the main body of the hull. This hinge line is the lineabout which the winglets pivot from their horizontal position to theirvertical position.

FIG. 3 is a side view of the marine vehicle with the winglets 20 in thevertical position as they would be at speeds below about twenty knots.The winglets 20 contain auxiliary propulsors 27 and are fitted withrudders 28 for low speed maneuvering. The winglet hinge line 26 is againshown.

FIG. 4 is a perspective view of the marine vehicle with the winglets 20in the partially raised position as they would be during the transitionfrom hull-borne to foil-borne operation. The tips of the winglets 20 arefitted with two or more planing surfaces with chines 27 to generateplaning lift during the time when these winglets are in the water. Inthis condition, the winglets 20 inhibit the circulation of air laterallyaround the wing tips thereby increasing the pressure beneath theaerodynamic surfaces of the main body 22.

FIG. 5 shows an inclined shaft 28 propulsion system fitted with one ormore in-water propellers 25.

FIG. 6 shows an in-air propulsion system with a puller propeller 31.

FIG. 7 shows an in-air propulsion system with a pusher propeller 32.

FIG. 8 shows the winglet flaps 25 that were previously described aslow-speed rudders, now providing aileron functions when the vehicle hastransitioned to high speed operation and the deployable winglets haverotated into the horizontal position. FIG. 8 also shows vertical controlsurfaces 33 to provide yaw control. FIG. 8 shows both in-air andin-water propellers although any one vehicle would normally have onlyone main propulsion system.

FIG. 9 is a representation of the changes in lift and control forces andmoments as a function of vehicle speed.

Description of the Prior Art

Lake was granted U.S. Pat. No. 1,307,135 for a seaplane float thatincluded a combination of hydrostatic and hydrodynamic features toreduce friction and cushion the impact of a hydroplane float duringlanding and takeoff. This invention included a means for injecting airbetween transverse aquafoils that are embedded in the float. The patentis relevant in that it is an early invention that combines three liftmechanisms operating in concert at the air-sea boundary. The particularcombination includes hydrostatic lift (buoyant floats), pressurized aircavity lift (exhaust gas injected between the aquafoils), andhydrodynamic lift (aquafoils).

Dickenson et al. were issued U.S. Pat. No. 2,343,645 for a folding wingthat was designed to accommodate the particular needs of a seaplane. Theinvention is relevant to the present invention to the extent that itspecifically accommodated buoyant floats on a movable wing that wasdesigned to withstand structural loads at all positions.

La Fleur was granted U.S. Pat. No. 3,064,370 for a dredge with buoyantcylindrical sponsons that could be moved vertically on hinged arms tochange the draft of the floating vessel. This invention described theconcept of deployable buoyancy on rotating arms that provided the vesselwith shallow draft, variable beam, and high transverse waterplaneinertia. The patent is relevant in that it establishes the art ofvertically deploying buoyancy about a swinging arm at the sides of amarine vessel.

Mathews was granted U.S. Pat. No. 3,485,198 for a boat with deployableflotation sponsons. Like La Fleur, this invention allows variations indraft, beam, and waterplane inertia. This patent extends the art toinclude variable planing surface area and new deployment mechanisms.

Austin was granted U.S. Pat. No. 3,918,382 for a twin-hull marine vesselthat combined lift from aerodynamic surfaces with lift from planingsurfaces. The aerodynamic lift is derived from an airfoil that bridgesbetween catamaran hulls. This invention included a flap on the trailingedge of the airfoil that was used to close the aft end of the cavityformed between the catamaran hulls thereby increasing the lift of theairfoil due to a higher pressure on the under side of the foil. Alongwith other ground-effect patents (e.g., Weston, U.S. Pat. No. 3,952,678)with different hull configurations, the art of combined hydrostatic,planing, and aerodynamic lift was recorded.

Westfall was granted U.S. Pat. No. 4,237,810 for a boat that combinedhydrodynamic and aerodynamic lift. Although similar to other multi-hullhydroplanes described earlier, this invention included skis thataugmented the lift force provided by the aerodynamic surfaces. There areno aerodynamic lifting surfaces in this patent.

Daniel was granted U.S. Pat. No. 4,452,166 for a foil stabilizedmonohull. Like La Fleur and Matthews, this invention used deployablebuoyancy to control the draft and stability of a marine vessel. Thispatent is relevant in its addition of foil stabilizers to maintainvessel stability once the outboard buoyancy is retracted. These foilswere not intended to produce vessel lift but rather to stabilize thehull.

Genfan was granted U.S. Pat. No. 4,964,357 for a planing boat that hadmoveable aerodynamic wings in ground effect, a fixed hydrofoil locatedforward, and buoyant sponsons on the tips of the wings. The invention isrelevant to the extent that it incorporated movable aerodynamicsurfaces, including buoyant pods, from a planing hull that getsadditional lift from a hydrofoil mounted beneath the forward end of thehull. The buoyant pods do not generate aerodynamic lift.

Rorabaugh et al. were granted U.S. Pat. No. 5,544,607 for movablesponsons on a hydrofoil watercraft. While earlier patents hadestablished the art of deployable buoyancy for enhanced stability anddraft control, Rorabaugh extended this art to the particular applicationof a pure hydrofoil craft. The deployable sponsons of Rorabaugh do notgenerate aerodynamic lift.

Roccotelli was granted U.S. Pat. No. 5,813,358 for a trimaran vesselthat incorporated a wing in ground effect that is located above thethree hydrostatic (trimaran) hulls, and three struts that includedsubmerged foils used for vessel stabilization and propulsion. Thisinvention had retractable winglets that pivoted vertically up. Theinvention is relevant in that it combined the aerodynamic lift of a wingin ground effect with the hydrostatic lift of a trimaran hull and thestabilizing effect of submerged foils. This invention did not envisionshared lift between the hydrofoils and the wing.

Jacobson was granted U.S. Pat. No. 6,014,940 for a seaplane thatoperates in ground effect. The patent is relevant to the extent that itenvisions a combination of planing and aerodynamic lift in a craft thatoperates in ground effect. Like the subject of this patent, theinvention uses a thick wing section to achieve high levels of lift inclose proximity to the water surface. Although the invention hasretractable winglets, these retract vertically upwards to minimizevessel beam when stowed. The invention does not describe hydrofoillifting surfaces.

Magazzu' was awarded U.S. Pat. No. 4,955,312 for a controlled geometryhydrofoil vessel. This craft embodies a variable-geometry deployablehydrofoil arrangement that is relevant to the extent that it provides avariation in the lift surface geometry as a function of speed. Theinvention does not use aerodynamic lift.

Burg was granted U.S. Pat. No. 6,199,496 for a hybrid air-cushionground-effect vehicle. This invention uses a pressurized cavity betweenhydrostatic hulls to generate an air cushion, has winglets that operatein ground effect, and uses a submerged retractable foil to stabilize thevessel. Unlike the present invention, this craft is a surface effectvehicle that derives its primary lift by pumping high pressure gas intoa cavity beneath the hull.

Fischer and Matjasic were awarded U.S. Pat. No. 6,230,835 B1 for aground effect vehicle. The invention claims a series of aerodynamicimprovements that result from coupled operation ofvertically-articulated winglets and wing flaps. The patent is relevantin that it cites resiliently mounted winglets that mitigate thestructural loads associated with winglet immersion in the water atspeed.

Burg was granted a second U.S. Pat. No. 6,546,886 B2, in which heexpanded his claims relative to surface effect multihull vehicles thatreceive additional aerodynamic support from retractable winglets. Thesewinglets retract vertically and do not provide buoyancy.

Markie was awarded U.S. Pat. No. 6,990,918 B2 for a marine vessel withupwardly retractable winglets that provide aerodynamic lift in groundeffect when they are deployed in a horizontal position. This inventiondoes not include hydrofoil lift and the winglets are retractedvertically upward.

SUMMARY OF THE INVENTION

The invention uses a combination of lift mechanisms to achieve highlift-to-drag ratios, low motions, good propulsion efficiency, and usefulinternal volume through wide ranges of vehicle speed, relative windconditions, and wave conditions. Furthermore, the vehicle has deployablewinglets that enable it to maintain a relatively shallow draft at allspeeds. The invention seeks reduced fuel consumption in high-speedmarine vehicles that have shallow draft. The hybrid combination of liftmechanisms (aerodynamic, hydrodynamic, and hydrostatic) also provide ahigh level of control authority that is necessary to actively reduce themotions of the vessel throughout the operating speed range therebyreducing the marine vehicle's motions in waves. The combination ofWing-In-Ground effect (WIG) and hydrofoil lift at the higher operatingspeeds, provides a high lift-to-drag ratio thereby reducing theinstalled engine power and fuel consumption.

1. A marine vehicle that has two force-generating elements that work inconcert to provide lift and control forces across a broad range ofoperating conditions, said force generating elements being: anaerodynamic wing operating in ground effect, and one or more hydrofoilsoperating at or beneath the water surface.
 2. The marine vehicledescribed in claim 1 fitted with subcavitating foils.
 3. The marinevehicle described in claim 1 fitted with supercavitating foils.
 4. Themarine vehicle described in claim 1 fitted with transcavitating foils.5. The marine vehicle described in claim 1 that is propelled with one ormore in-water propellers.
 6. The marine vehicle described in claim 1that is propelled by one or more waterjets.
 7. The marine vehicledescribed in claim 1 that is propelled with an in-air propeller.
 8. Themarine vehicle described in claim 1 that is propelled with an in-airducted fan.
 9. The marine vehicle described in claim 1 thatprogressively transitions from a speed regime where the majority of thelift is generated by the hydrofoils to a regime where the majority ofthe lift is generated by aerodynamic surfaces.
 10. The marine vehicledescribed in claim 1 that is in a speed regime where the primary liftforce is generated aerodynamically but the vehicle control forces aregenerated hydrodynamically by the controllable hydrofoils.
 11. Themarine vehicle described in claim 1 where the aerodynamic liftingsurface is of sufficient thickness to house people and or materialsduring marine transport.
 12. The marine vehicle described in claim 1that has horizontal and vertical aerodynamic control surfaces togenerate yaw forces and to bias the port/starboard lift percentages asmay be necessary to operate in cross-wind conditions.
 13. The marinevehicle described in claim 1 that has flaps on the trailing edges of theaerodynamic surfaces that are employed to control the gap between theaerodynamic surface and the sea surface, thereby controlling the liftgenerated from the aerodynamic surface. Said flaps are mechanicallyactuated and may have resilient elements to avoid structural damage uponwave impact.
 14. The marine vehicle described in claim 1 that hasaerodynamic and hydrodynamic lift and control forces developed in-airand in-water under the control of algorithms that optimize vehiclelift-to-drag ratio and stability as a function of vehicle speed,relative wind, vehicle load, vehicle center of gravity, sea wavespectra.
 15. The marine vehicle described in claim 1 that may have asurface that reduces its radar cross section.
 16. A marine vehicle thathas deployable winglets to provide aerodynamic lift and control forcesas well has hydrodynamic planing forces and hydrostatic buoyant forces.When in the horizontal position, the winglets generate aerodynamic liftand control forces. When rotated downward, the winglets formhydrodynamic planing surfaces and hydrostatic buoyancy. When deployeddownward, the winglets transform the outward extents of the aerodynamicsurfaces into one or more buoyant hulls that provide planing lift andbuoyancy to support the craft at low and zero speeds while achieving lowvessel motions and while avoiding the need to retract other propulsion,lift or control appendages to achieve shallow draft.
 17. The marinevehicle described in claim 16 that transitions from low-speed hull-borneoperation to high-speed operation by raising the winglets from adownward vertical position to a horizontal position as the speed of thevehicle increases and the combined lift of the aerodynamic and orhydrofoil surfaces is equal to or greater than the vehicle weight. 18.The marine vehicle described in claim 16 that has control algorithmsprovide real-time vehicle control by commanding the coordinatedactuation of control surfaces that are located in the air and in thewater. The control algorithms vary as a function of vehicle speed toobtain robust control characteristics throughout the speed range. 19.The marine vehicle described in claim 16 that is fitted with low-speedpropulsion systems in the deployable winglets thereby minimizing theneed to operate high-power propulsion systems during low speed andloiter operations.
 20. The marine vehicle described in claim 16 thatuses the control flaps on the aft surfaces of the deployable winglets asboth in-air ailerons and in-water rudders depending upon the position ofthe deployable winglets.
 21. A marine vehicle that has three mechanismsto generate lift and control forces, said mechanisms being: aerodynamiclift from a wing operating in ground effect, hydrodynamic lift generatedfrom one or more hydrofoils, and buoyant and or planing lift generatedby downwardly deployable winglets whose position can be infinitelyvaried from horizontal to vertical. When in the horizontal position, thewinglets generate aerodynamic lift and control forces. When rotateddownward, the winglets form hydrodynamic planing surfaces andhydrostatic buoyancy. When deployed downward, the winglets transform theoutward extents of the aerodynamic surfaces into one or more buoyanthulls that provide planing lift and buoyancy to support the craft at lowand zero speeds while achieving low vessel motions and while avoidingthe need to retract other propulsion, lift or control appendages toachieve shallow draft.
 22. The marine vehicle described in claim 21fitted with subcavitating foils.
 23. The marine vehicle described inclaim 21 fitted with supercavitating foils.
 24. The marine vehicledescribed in claim 21 fitted with transcavitating foils.
 25. The marinevehicle described in claim 21 that is propelled with one or morein-water propellers.
 26. The marine vehicle described in claim 21 thatis propelled by one or more waterjets.
 27. The marine vehicle describedin claim 21 that is propelled with an in-air propeller.
 28. The marinevehicle described in claim 21 that is propelled with an in-air ductedfan.
 29. The marine vehicle described in claim 21 that, as speed isincreased, undergoes a progressive transition from the majority of thelift being generated by hydrofoils, to the majority of the lift beinggenerated by aerodynamic surfaces.
 30. The marine vehicle described inclaim 29 that is in a speed regime where the primary lift force isgenerated aerodynamically but the vehicle control forces are generatedhydrodynamically by the controllable hydrofoils.
 31. The marine vehicledescribed in claim 21 where the aerodynamic lifting surface is ofsufficient thickness to house people and or materials during marinetransport.
 32. The marine vehicle described in claim 21 that hashorizontal and vertical aerodynamic control surfaces to generate yawforces and to bias the port/starboard lift percentages as may benecessary to operate in cross-wind conditions.
 33. The marine vehicledescribed in claim 21 that has flaps on the trailing edges of theaerodynamic surfaces that are employed to control the gap between theaerodynamic surface and the sea surface, thereby controlling the liftgenerated from the aerodynamic surface. Said flaps are mechanicallyactuated and may have resilient elements to avoid structural damage uponwave impact.
 34. The marine vehicle described in claim 21 that hasaerodynamic and hydrodynamic lift and control forces developed in-airand in-water under the control of algorithms that optimize vehiclelift-to-drag ratio and stability as a function of vehicle speed,relative wind, vehicle load, vehicle center of gravity, sea wavespectra.
 35. The marine vehicle described in claim 21 that may have asurface that reduces its radar cross section.
 36. The marine vehicledescribed in claim 21 that transitions from low-speed hull-borneoperation to high-speed operation by raising the winglets from adownward vertical position to a horizontal position as the speed of thevehicle increases and the combined lift of the aerodynamic and orhydrofoil surfaces is equal to or greater than the vehicle weight. 37.The marine vehicle described in claim 21 that is fitted with low-speedpropulsion systems in the deployable winglets thereby minimizing theneed to operate high-power propulsion systems during low speed andloiter operations.
 38. The marine vehicle described in claim 21 thatuses the control flaps on the aft surfaces of the deployable winglets asboth in-air ailerons and in-water rudders depending upon the position ofthe deployable winglets.